Researchers examined responses from Ontario health surveys — such as the Community Health Survey from Statistics Canada — then compiled the information to plug into theirsurvival models

that analyzed approximately 80,000 virtual people who lived with combinations of these five deadly habits.

Of these virtual people, researchers watched to see who died during theseven human years that passed.

Dr. Doug Manuel, lead author and senior scientist at the Institute for Clinical Evaluative Sciences in Toronto, says everyone has at least one health issue that needs to be addressed and this study helps people decipher what they need to eliminate from their lives to live longer.

If we all make one change like smoking less or being more physically active, then collectively we would be a lot healthier and live much longer,said Manuel.

We believe this data could work for all Canadians. We believe it could even be helpful for people in other countries. But for now, in Ontario, we feel pretty good about the science.

Using the results of the report, the Institute for Clinical Evaluative Sciences has created an online life expectancy calculator, to involve individual people in the science behind the study. Following a questionnaire, participants are given their 'expected age of death' and the number 1 habit that would affect this number.

Dr. Vivek Goel, president and chief executive officer of Public Health Ontario, said the calculator is a good guide for comparing your health to others.

It is all mathematical probability,said Goel.Your results compare you to others in the province with the same answers, sex and age as you. It is not so much individualized as a good model for your demographic.

Dr. Scott Kush, a medical researcher for the Life Expectancy Group, warns life expectancy surveys on the Internet could be very dangerous because key data are generally left out.

Misinformation is worse than no information,said Kush.When you take these surveys, you have to think, 'Will it miss the person with the brain disease?' or, 'Will it see the person who has cancer?' Unless you're going to take a thorough look at someone, are you going to come back with real results?

But Mark Tremblay, director of healthy active living and obesity research at the Children's Hospital of Eastern Ontario in Ottawa, says although these surveys cannot be lumped together, they may have motivating factors for individuals.

When you apply risk factors, it could mean one thing to you and a different thing to me,said Tremblay.If they motivate an individual, though, the harm is minimal.

No margin of error was given for the study due to the large number of factors "outside of researchers' control."